Method for manufacturing display panel

ABSTRACT

A method for manufacturing a display panel, including defining a desorbing area of a support substrate by forming one of a release layer or a recess portion in the desorbing area, cleaning a surface of the support substrate, disposing a thin film substrate on the support substrate, directly bonding, in an adsorbing area external to the desorbing area, the thin film substrate to the support substrate, forming a pixel and a sealing member on the thin film substrate, cutting the sealing member and the thin film substrate at a location that corresponds to the desorbing area, and separating the support substrate from the thin film substrate.

CLAIM OF PRIORITY

This application claims priority to and the benefit of Korean PatentApplication No. 10-2013-0141610 filed in the Korean IntellectualProperty Office on Nov. 20, 2013, the entire contents of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The described technology relates generally to a method for manufacturinga display panel.

2. Description of the Related Art

Recently, the display device market has been rapidly changing to a flatpanel display (FPD) market because the FPDs may be easily implemented tobe large, thin, and lightweight. Among various types of flat paneldisplays, an organic light emitting diode (OLED) display is aself-emitting type without a separate light source and therefore is moreadvantageous in thinness and weight reduction.

Since a general flat panel display uses a glass substrate, the flatpanel display has reduced flexibility, a thick thickness, and a heavyweight, and therefore is limited in applications. Recently, to reducethe thickness of the display device, display units are being formed onan ultrathin glass substrate.

The ultrathin glass substrate has a thin thickness and a large area, andtherefore is not easy to handle. Therefore, a support substrate isattached beneath the ultrathin glass substrate in order to form a pixelon the ultrathin glass substrate.

However, after the pixel formation process is completed, the ultrathinglass substrate needs to be separated from the support substrate. Inorder to do so, the ultrathin glass substrate is exposed to a hightemperature process and the like, and therefore may not be easilyseparated from the support substrate and may be partially damaged.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the describedtechnology, and therefore it may contain information that does notconstitute prior art as per 35 U.S.C. §102.

SUMMARY OF THE INVENTION

Therefore, the present invention has been made in an effort to provide amethod for manufacturing a display panel capable of easily separating anultrathin glass substrate from a support substrate.

According to one aspect of the present invention, there is provided amethod of manufacturing a display panel, including defining a desorbingarea in a support substrate by forming one of a release layer and arecess portion in the desorbing area of the support substrate, cleaninga surface of the support substrate, disposing a thin film substrate onthe support substrate, bonding the thin film substrate to the supportsubstrate, forming a pixel and a sealing member on the thin filmsubstrate, cutting the sealing member and the thin film substrate at alocation that corresponds to the desorbing area and separating thesupport substrate from the thin film substrate. The cleaning may beachieved by one of UV cleaning, ultrasonic wave cleaning, waterjetcleaning, hydrogen water cleaning, and ozone (O₃) cleaning. The pixelmay include an organic light emitting element.

The desorbing area may be defined by the recess portion, the recessportion being produced by plasma etching or sandblasting. A depth of therecess portion may be 2 nm to 200 μm. The desorbing area may be definedby the release layer, the forming of the release layer may includeforming one of an indium tin oxide (ITO) layer and an indium zinc oxide(IZO) layer on the support substrate, forming a reserved release layerby patterning the one of the ITO layer and the IZO layer andcrystallizing the reserved release layer. The release layer may beformed to have a thickness of 100 Å to 1,000 Å.

The thin film substrate may include an ultrathin glass having athickness of 0.01 mm to 0.1 mm. A surface roughness of the supportsubstrate at a location corresponding to an adsorbing area external tothe desorbing area may be equal to or less than 0.2 nm. During thebonding, the thin film substrate may be directly and covalently bondedto the support substrate in the adsorbing area without an interveningadhesive layer.

According to another aspect of the present invention, there is providedanother method of manufacturing a display panel, including cleaning asurface of a support substrate, defining a desorbing area of the supportsubstrate by forming one of a release layer and a recess portion in thedesorbing area of the support substrate, disposing a thin film substrateon the support substrate, bonding the thin film substrate to the supportsubstrate, forming a pixel and a sealing member on the thin filmsubstrate, cutting the sealing member and the thin film substrate at alocation that corresponds to the desorbing area and separating thesupport substrate from the thin film substrate. The cleaning may includea process selected from UV cleaning, ultrasonic wave cleaning, waterjetcleaning, hydrogen water cleaning, and ozone (O₃) cleaning, and the thinfilm substrate may be directly and covalently bonded to the supportsubstrate in an adsorbing area external to the desorbing area andwithout an intervening adhesive layer. The support substrate may alsoinclude an adsorbing area surrounding the desorbing area.

The desorbing area may be defined by the recess portion, the recessportion may be produced by etching the support substrate via a processselected from a group consisting of plasma etching and sandblasting. Adepth of the recess portion may be 2 nm to 200 μm.

The desorbing area may be defined by the release layer, the forming ofthe release layer may include forming one of an indium tin oxide (ITO)layer and an indium zinc oxide (IZO) layer on the support substrate,forming a reserved release layer by patterning the one of the ITO layerand the IZO layer and crystallizing the reserved release layer. Therelease layer may be formed to have a thickness of 100 Å to 1000 Å.

The thin film substrate may be an ultrathin glass having a thickness of0.01 mm to 0.1 mm. A surface roughness of the support substrate at alocation corresponding to an adsorbing area external to the desorbingarea may be equal to or less than 0.2 nm. The pixel may include anorganic light emitting element.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention, and many of the attendantadvantages thereof, will be readily apparent as the same becomes betterunderstood by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings, in which likereference symbols indicate the same or similar components, wherein:

FIG. 1 is a flowchart illustrating a method for manufacturing a displaypanel according to a first exemplary embodiment of the presentinvention;

FIG. 2 illustrates a process step where a release layer is added to adesorbing area SA of the support substrate according to the method ofthe first exemplary embodiment;

FIG. 3 illustrates a process of where a thin film substrate is attachedto the support substrate/release layer combination according to themethod of the first exemplary embodiment;

FIG. 4 illustrates a process step where a pixel is formed on the thinfilm substrate attached to the support substrate according to the methodof the first exemplary embodiment;

FIG. 5 illustrates a process step where the display panel including thepixel and a portion of the thin film substrate are separated from thesupport substrate according to the method of the first exemplaryembodiment;

FIG. 6 is a schematic layout view of a display panel in a mothersubstrate according to an exemplary embodiment of the present invention;

FIG. 7 is a schematic layout view of an organic light emitting displaypanel according to an exemplary embodiment of the present invention;

FIG. 8 is an equivalent circuit diagram illustrating one pixel of theorganic light emitting display panel according to an exemplaryembodiment of the present invention;

FIG. 9 is a cross-sectional view of one pixel of an organic lightemitting diode (OLED) display of FIG. 8;

FIG. 10 is a flowchart illustrating a sequence of manufacturing adisplay panel according to a second exemplary embodiment of the presentinvention;

FIG. 11 is a cross-sectional view of the display panel in theintermediate step depending on the sequence of FIG. 10 according to themethod of the second exemplary embodiment;

FIG. 12 is a flowchart illustrating a sequence of manufacturing adisplay panel according to a third exemplary embodiment of the presentinvention; and

FIG. 13 is a cross-sectional view of the display panel in anintermediate step according to the method of the third exemplaryembodiment.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, the exemplary embodiment will be described more fully withreference to the accompanying drawings, in which exemplary embodimentsare shown. As those skilled in the art would realize, the describedembodiments may be modified in various different ways, all withoutdeparting from the spirit or scope of the present invention.

In the drawings, the thickness of layers, films, panels, regions, etc.,are exaggerated for clarity. It will be understood that when an elementsuch as a layer, film, region, or substrate is referred to as being “on”another element, it can be directly on the other element or interveningelements may also be present. In contrast, when an element is referredto as being “directly on” another element, there are no interveningelements present.

Turning now to FIG. 1, FIG. 1 is a flowchart illustrating a method formanufacturing a display panel according to an exemplary embodiment. Asillustrated in FIG. 1, a method for manufacturing a display panelaccording to an exemplary embodiment includes forming a desorbing areaand an adsorbing area on a support substrate (S100), cleaning thesupport substrate (S102), bonding a thin film substrate onto the supportsubstrate (S104), forming a pixel on the thin film substrate (S106),cutting the thin film substrate into individual display panels (S108),and separating the display panel from the support substrate (S110).

Hereinafter, the method for manufacturing a display panel according tothe flowchart of FIG. 1 will be described in detail with reference toFIGS. 2 to 5.

FIGS. 2 to 5 are cross-sectional views schematically describing themethod for manufacturing a display panel according to the firstexemplary embodiment, and FIG. 6 is a schematic layout view of a displaypanel in a mother substrate according to the first exemplary embodiment.

As illustrated in FIGS. 1 and 2, a support substrate 500 is prepared anda release layer 10 is formed on the support substrate 500 (S100) todifferentiate a desorbing area SA from an adsorbing area SB.

The support substrate 500 supports the thin film substrate 100 andprevents the thin film substrate from warping, which would otherwiseoccur because the thin film substrate, often made out of a glasssubstrate, is very thin. The support substrate 500 may have a thicknessof 0.3 mm to 1 mm, and may preferably have a thickness of 0.5 mm.

The desorbing area SA is a region in which the release layer 10 isformed, and the adsorbing area SB is a region in which the release layer10 is not formed. As illustrated in FIG. 6, the release layer may beformed in plural and disposed in a matrix form.

For the release layer, an indium tin oxide (ITO) film or an indium zincoxide (IZO) film is first formed to a thickness of 100 Å to 1000 Å at atemperature of 200° C. or less. Next, a reserved release layer is formedby patterning the ITO film or the IZO film using a photolithographyprocess.

In this case, the ITO film is an amorphous thin film, and since the ITOfilm may be coupled to the thin film substrate by reacting with the thinfilm substrate at the time of undergoing a subsequent heat treatment,the amorphous ITO film is poly-crystallized by being heat-treated at atemperature of 400° C. for 30 minutes. When the amorphous ITO film iscrystallized, a surface roughness of the ITO film is increased tominimize a contact area with the thin film substrate 100, and thus theITO film does not couple to the thin film substrate even though the ITOfilm undergoes a subsequent heat treatment.

Compared to the ITO film, the IZO film has relatively less reactivitywith the thin film substrate and does not need to undergo thecrystallization process, but is crystallized and thus may be more easilydetached.

Next, the support substrate 500 is cleaned (S102). The cleaning removesorganic material on a surface of the substrate 500, and exposed portionsof the substrate 500 corresponding to the adsorbing area SB becomehydrophilic by attaching an OH group onto the surface thereof.

For the cleaning process, UV cleaning, ultrasonic wave cleaning,waterjet cleaning, hydrogen water cleaning, ozone (O₃) cleaning, and thelike may be performed. The UV cleaning may be performed at a wavelengthof 172 nm for 65 seconds, the ultrasonic wave cleaning may be performedat a power of 600 W, the waterjet cleaning may be performed at apressure of 90 bar and at a specific resistance value of 0.8 MΩ, and theozone cleaning may be performed for 55 seconds when an ozoneconcentration is 25 ppm.

Next, as illustrated in FIGS. 1 and 3, a thin film substrate 100 isdisposed on the support substrate 500 to contact the support substrate500, and is then bonded to the support substrate 500 (S104). The thinfilm substrate 100 is thinner than the support substrate 500, and may bean ultrathin glass substrate having a thickness of 0.01 mm to 0.1 mm.The bonding is performed in a vacuum state of 10E-1 torr or less, or maybe performed at a temperature of 250° C. or more for 10 minutes. Inaddition, a compressive force may also be applied between the thin filmsubstrate and the support substrate to form the bond.

The support substrate 500 and portions of the thin film substrate 100that are located at the attaching area SB at the time of the directbonding contact each other and thus are chemically coupled with eachother. Portions of the thin film substrate 100 located in the desorbingarea SA are physically coupled to the release layer 10 by contacting therelease layer 10.

That is, oxygen (O) attached to the support substrate 500 and the thinfilm substrate 100 as a result of the cleaning, and then Si of thesubstrates are covalently bonded through the oxygen (O), such that thesupport substrate 500 and the thin film substrate 100 are stronglycoupled to each other.

However, in the desorbing area SA, the release layer 10 does not includeSi, and therefore covalent bonding does not occur. In the desorbing areaSA, the release layer 10 and the thin film substrate 100 are physicallycoupled to each other, such that the thin film substrate 100 and thesupport substrate 500 are more weakly coupled than in the adsorbing areaSB. FIG. 3 illustrates thin film substrate 100 mounted on supportsubstrate 500 with release layer 10 formed thereon, however in FIG. 3,the thickness of the release layer 10 is grossly exaggerated to recitethe structure, and it is to be appreciated that the thickness of therelease layer 10 is very thin (100 Å to 1000 Å thick), so that a topsurface of the release layer 10 is nearly flat.

Meanwhile, the thin film substrate 100 may be a mother substrate onwhich the display panel 300, including a plurality of pixels for anorganic light emitting display panel or a liquid crystal display panel,are formed in plural, and each display panel 300 is located within aboundary line of a corresponding desorbing area SA. In this case, asillustrated in FIG. 6, the support substrate 500 may be provided withthe plurality of desorbing areas SA corresponding to a plurality ofrelease layers 10, and may be disposed in a matrix form. Therefore, theadsorbing area SB is located between the neighboring desorbing areas SA,such that the desorbing areas SA is surrounded by the adsorbing area SB.

When the desorbing area SA is formed to be biased to one side of thesupport substrate 500 and thus the adsorbing area SB does not surroundthe desorbing area SA, or only the desorbing area SA is formed over thewhole of the support substrate 500, since the release layer 10 ispresent between the thin film substrate 100 and the support substrate500, a peeling phenomenon may occur between the two substrates.Therefore, the adsorbing area SB is formed to surround the desorbingarea SA to prevent the thin film substrate 100 and the support substrate500 from separating from each other.

Meanwhile, the surface roughness of the adsorbing area SB of the supportsubstrate 500 may be 0.2 nm or less. When the surface roughness of theadsorbing area SB exceeds 0.2 nm, the peeling phenomenon may occur dueto air bubbles, even though the adsorbing area SB becomes hydrophilic bythe cleaning.

Next, as illustrated in FIGS. 1 and 4, a plurality of pixels 120 of theorganic light emitting display panel are formed on the thin filmsubstrate 100. The pixel structure will be now described in detail withreference to FIGS. 7 to 9.

FIG. 7 is a schematic layout view of the organic light emitting displaypanel according to the exemplary embodiment. Referring to FIG. 7, thepixel 120 of the organic light emitting display panel is formed on thethin film substrate 100 and may be disposed in a matrix form.

The organic light emitting display panel is formed on the thin filmsubstrate 100, and includes a display unit PA which includes theplurality of pixels, and a driver PB which includes a driving circuitconnected to the pixels.

The display unit PA is formed in one direction and includes a firstsignal line 121 which transfers a scanning signal, a second signal line171 which intersects the first signal line 121 and transfers a datasignal, and the pixels 120 which are disposed in a matrix form, areconnected to the first signal line 121 and the second signal line 171 todisplay images. The pixel may be connected to various additional signallines to which other signals may be applied, in addition to the firstsignal line and the second signal line.

The pixel 120 includes thin film transistors and organic light emittingelements which receive the signals from the first signal line 121 andthe second signal line 171 to display images. The organic light emittingelement is controlled by the driver PB and emits light depending on thedriving signal to display an image.

The driver PB includes driving circuits 400 that are each connected tothe first signal line 121 or the second signal line 171 to transferexternal signals. The driving circuit 400 is mounted on the thin filmsubstrate in an IC chip form, or may be integrated on the thin filmsubstrate 100 along with the thin film transistor of the display unit.

One pixel of the organic light emitting display panel will be describedin more detail with reference to FIG. 8.

FIG. 8 is an equivalent circuit diagram illustrating one pixel of anorganic light emitting display panel according to an exemplaryembodiment. As illustrated in FIG. 8, the organic light emitting displaypanel according to the exemplary embodiment includes the plurality ofsignal lines 121, 171, and 172 and the pixels 120 connected thereto.

The signal lines includes a gate line 121 which transfers the scanningsignal, a data line 171 which transfers the data signal, and a drivingvoltage line 172 which transfers a driving voltage, and the like. Thegate line may be a first signal line of FIG. 7 and the data line may bea second signal line of FIG. 7.

The gate lines 121 approximately extend in a row direction and areapproximately parallel with each other, and the data lines 171approximately extend in a column direction and are approximatelyparallel with each other. The driving voltage line 172 approximatelyextends in the column direction, but may extend in the row direction orthe column direction or may also be formed in a net shape.

One pixel 120 includes a switching transistor Qs, a driving transistorQd, a capacitor Cst, and an organic light emitting element 70. Theswitching transistor Qs includes a control terminal, an input terminal,and an output terminal, in which the control terminal is connected tothe gate line 121, the input terminal is connected to the data line 171,and the output terminal is connected to the driving transistor Qd. Theswitching transistor Qs transfers the data signal received from the dataline 171 to the driving transistor Qd in response to the scanning signalreceived from the gate line 121.

The driving transistor Qd also has a control terminal, an inputterminal, and an output terminal, in which the control terminal isconnected to the switching transistor Qs, the input terminal isconnected to the driving voltage line 172, and the output terminal isconnected to the organic light emitting element 70. The drivingtransistor Qd transfers an output current Id of which the magnitudevaries depending on a voltage applied between the control terminal andthe output terminal.

The capacitor Cst is connected between the control terminal and theinput terminal of the driving transistor Qd. The capacitor Cst chargesthe data signal applied to the control terminal of the drivingtransistor Qd and maintains the charged data signal even after theswitching transistor Qs is turned off.

The organic light emitting element 70 is, for example, an organic lightemitting diode (OLED), and includes an anode which is connected to theoutput terminal of the driving transistor Qd and a cathode which isconnected to a common voltage Vss. The organic light emitting element 70displays an image by emitting light of which the strength variesdepending on the output current Id of the driving transistor Qd. Theorganic light emitting element 70 may include an organic material whichuniquely emits light of any one of primary colors such as three primarycolors of red, green, and blue, or at least one light, and the organiclight emitting diode display displays a desired image by a spatial sumof these colors.

FIG. 9 is a cross-sectional view of one pixel of an organic lightemitting diode (OLED) display of FIG. 8.

A stacked sequence of the driving transistor Qd and the switchingtransistor Qs is the same, and therefore, in FIG. 9, the drivingtransistor Qd and the organic light emitting element 70 of FIG. 8 willbe mainly described in detail according to the stacking sequence.Hereinafter, the driving thin film transistor Qd is referred to as athin film transistor.

As illustrated in FIG. 9, the organic light emitting display panelincludes the substrate 100, and a buffer layer 110 is formed on thesubstrate 100. The substrate 100 is the thin film substrate of FIG. 2and may be an ultrathin glass substrate. The buffer layer 110 may beformed to have a single layer of silicon nitride (SiNx) or a doublelayer structure in which a silicon nitride (SiNx) layer and a siliconoxide (SiO_(x)) layer are stacked. The buffer layer 110 serves toplanarize the surface while preventing infiltration of impurities suchas moisture or oxygen.

A semiconductor 135 made of polysilicon is formed on the buffer layer110. The semiconductor 135 is divided into a channel region 1355, and asource region 1356 and a drain region 1357 which are formed atrespective sides of the channel region 1355. The channel region 1355 ofthe semiconductor is polysilicon which is not doped with an impurity,such as an intrinsic semiconductor. The source region 1356 and the drainregion 1357 are polysilicon doped with a conductive impurity and areextrinsic semiconductors. The impurity doped in the source region 1356and the drain region 1357 may be any one of a p-type impurity and ann-type impurity.

A gate insulating layer 140 is formed on the semiconductor 135. The gateinsulating layer 140 may be a single layer or multiple layers includingat least one of tetraethyl orthosilicate (TEOS), a silicon nitride, anda silicon oxide.

A gate electrode 155 is formed on the gate insulating layer 140 andoverlaps the channel region 1355. The gate electrode 155 may be formedas a single layer or multiple layers including a low resistance materialor a material that is resistant to corrosion, such as Al, Ti, Mo, Cu,Ni, or an alloy thereof.

A first interlayer insulating layer 160 is formed on the gate electrode155. The first interlayer insulating layer 160 may be formed as a singlelayer or multiple layers including tetraethyl orthosilicate (TEOS),silicon nitride, silicon oxide, or the like, similar to the gateinsulating layer 140. The first interlayer insulating layer 160 and thegate insulating layer 140 are perforated by a source contact hole 166and a drain contact hole 167 through which the source region 1356 andthe drain region 1357 are respectively exposed.

A source electrode 176 and a drain electrode 177 are formed on the firstinterlayer insulating layer 160. The source electrode 176 is connectedto the source region 1356 through the contact hole 166 and the drainelectrode 177 is connected to the drain region 1357 through the contacthole 167. The source electrode 176 and the drain electrode 177 may beformed as a single layer or as multiple layers including a lowresistance material or a material resistant to corrosion, such as Al,Ti, Mo, Cu, Ni, or an alloy thereof. For example, the source electrode176 and the drain electrode 177 may be a three-layered structure such asof Ti/Cu/Ti, Ti/Ag/Ti, or Mo/Al/Mo.

The gate electrode 155, the source electrode 176, and the drainelectrode 177 form the thin film transistor, along with thesemiconductor 135. A channel of the thin film transistor is formed inthe channel region 1355 of the semiconductor 135 between the sourceelectrode 176 and the drain electrode 177.

A second interlayer insulating layer 180 is formed on the sourceelectrode 176 and the drain electrode 177. The second interlayerinsulating layer 180 is perforated by a contact hole 85 through whichthe drain electrode 177 is exposed. The second interlayer insulatinglayer 180 may be formed as a single layer or as multiple layersincluding tetraethyl orthosilicate (TEOS), a silicon nitride, a siliconoxide, or the like, like the first interlayer insulating layer, and maybe made of an organic material having a low dielectric constant.

A first electrode 710 is formed on the second interlayer insulatinglayer 180. The first electrode 710 is electrically connected to thedrain electrode 177 through the contact hole 85, and the first electrode710 may be an anode of the organic light emitting element of FIG. 8.

According to the exemplary embodiment, the second interlayer insulatinglayer 180 is formed between the first electrode 710 and the drainelectrode 177, but the first electrode 710 may instead be formed on thesame layer as the drain electrode 177 and may be integrated with thedrain electrode 177.

A pixel definition layer 190 is formed on the first electrode 710. Thepixel definition layer 190 has an opening 195 through which the firstelectrode 710 is exposed. The pixel definition layer 190 may be made ofa resin such as polyacrylates or polyimides, silica-based inorganicmaterials, and the like.

An organic emission layer 720 is formed within the opening 195 of thepixel definition layer 190. The organic emission layer 720 is formed inmultiple layers including an emission layer and at least one of ahole-injection layer (HIL), a hole-transporting layer (HTL), anelectron-transporting layer (ETL), and an electron-injection layer(EIL). When the organic emission layer 720 includes all of the abovecomponents, the hole-injection layer (HIL) is disposed on the pixel (oranode) electrode 710, and the hole-transporting layer (HTL), theemission layer, the electron-transporting layer (ETL), and theelectron-injection layer (EIL) may be sequentially stacked thereon.

A second electrode 730 is formed on the pixel definition layer 190 andthe organic emission layer 720. The second electrode 730 is a cathode ofthe organic light emitting element. Therefore, the first electrode 710,the organic emission layer 720, and the second electrode 730 form theorganic light emitting element 70.

The organic light emitting diode display may have any one structure of atop emission display, a bottom emission display, and a dual emissiondisplay depending on the direction in which the organic light emittingelement 70 emits light. In the case of the front emission display, thefirst electrode 710 is formed of a reflective layer and the secondelectrode 730 is formed of a transflective layer or a transmissivelayer. On the other hand, in the case of the bottom emission display,the first electrode 710 is formed of the transflective layer and thesecond electrode 730 is formed of the reflective layer. Further, in thecase of the dual emission display, the first electrode 710 and thesecond electrode 730 are formed of a transparent layer or atransflective layer.

The reflective layer and the transflective layer are made of an at leastone of magnesium (Mg), silver (Ag), gold (Au), calcium (Ca), lithium(Li), chromium (Cr), and aluminum (Al), or an alloy thereof. Theelectrode is reflective layer or transflective layer based upon athickness of the layer comprising Mg, Ag, Au, Ca, Li, Cr and/or Al.Specifically, the electrode is transflective if the layer comprising Mg,Ag, Au, Ca, Li, Cr and/or Al is less than 200 nm thick. As the thicknessof the layer comprising Mg, Ag, Au, Ca, Li, Cr and/or Al decreases below200 nm thick, transmittance of light is increased, but when thethickness is too thin, resistance becomes excessive.

The transparent layer is made of a material such as indium tin oxide(ITO), indium zinc oxide (IZO), zinc oxide (ZnO), or indium oxide(In₂O₃).

A sealing member 260 is formed on the second electrode 730. The sealingmember 260 may include at least one organic layer and one inorganiclayer that may be alternately stacked. The organic layer may have anarrower area than that of the inorganic layer, such that the inorganiclayer may be formed to completely cover the organic layer.

The organic layer is made of a polymer, and may be a single layer or astacked layer which is made of any one of polyethylene terephthalate,polyimide, polycarbonate, epoxy, polyethylene, and polyacrylate. Morepreferably, the organic layer may be made of polyacrylate, and indetail, includes a material in which a monomer composition including adiacrylate-based monomer and a triacrylate-based monomer is polymerized.The monomer composition may further include a monoacrylate-basedmonomer. Further, the monomer composition may include a knownphotoinitiator such as TPO (Trimethylbenzoyl-diphenyl-phosphineoxide),but is not limited thereto.

The inorganic layer may be a single layer or a stacked layer including ametal oxide or a metal nitride. In detail, the inorganic layer mayinclude any one of SiNx, Al₂O₃, SiO₂, and TiO₂.

The uppermost layer exposed to the outside in the sealing member 260 maybe formed of the inorganic layer to prevent moisture from infiltratinginto the organic light emitting element. A halogenated metal layerincluding LiF may be additionally included between the second electrode730 and the sealing member 260. The halogenated metal layer may preventthe lower layer from being damaged when the first inorganic layer isformed by a sputtering method or a plasma deposition method.

As illustrated in FIGS. 1 and 5, each display panel 300 is completed bycutting the sealing member 260 and the thin film substrate 100 by usinga laser or wheel scribing process, and separating the support substrate500 from the thin film substrate 100. In this case, since the thin filmsubstrate 100 and the support substrate 500 are strongly coupled witheach other by the adsorbing area SB, the display panel 300 is separatedby cutting the thin film substrate 100 at a location that corresponds tothe desorbing area SA.

According to the exemplary embodiment, when the release layer 10 isformed and then the surface of the adsorbing area SB becomes hydrophilicdue to the cleaning, the thin film substrate 100 and the supportsubstrate 500 may be coupled with each other by strong covalent bonding,such that after the thin film substrate 100 is cut into each of thedisplay panels 300, the support substrate 500 may be easily removed fromthe cut display panels 300.

Meanwhile, according to the related art, the display panel 300 is formedand then the support substrate 500 is separated by a laser ablationtechnique, such that the transparency of the thin film substrate 100 maybe reduced. However, according to the exemplary embodiment, laserablation is not required to separate the support substrate 500 from thedisplay panels, such that the transparency of the thin film substrate100 of the display panel may not be reduced.

Hereinafter, a method for manufacturing an organic light emittingdisplay panel according to a second exemplary embodiment will bedescribed. Hereinafter, only characteristic portions differentiated fromthe first exemplary embodiment of FIG. 1 will be described in detail,and non-described portions are the same as or similar to the firstexemplary embodiment of FIG. 1.

FIG. 10 is a flowchart illustrating a sequence of manufacturing adisplay panel according to a second exemplary embodiment of the presentinvention, and FIG. 11 is a cross-sectional view of the display panel inan intermediate step according to the sequence of FIG. 10.

As illustrated in FIG. 10, the method for manufacturing a display panelaccording to the second exemplary embodiment includes cleaning thesupport substrate (S200), forming the release layer (S202), bonding thethin film substrate on the support substrate (S204), forming the pixelon the thin film substrate (S206), cutting the thin film substrate intoindividual display panels (S208), and separating the display panel fromthe support substrate (S210).

As illustrated in FIG. 11, the support substrate 500 is first cleaned,and then as illustrated in FIG. 2, the release layer 10 is formed, suchthat the desorbing area SA and the adsorbing area SB are differentiatedfrom each other.

As illustrated in FIG. 11, when the support substrate 500 is cleaned,the entire support substrate 500 has hydrophilicity. Therefore, when therelease layer 10 is formed on the support substrate 500 subsequent tothe cleaning, the hydrophilic surface is located below the release layer10, and the thin film substrate 100 contacts the upper surface of therelease layer 10 without bonding to the support substrate 500 atlocations corresponding to the release layer 10.

Therefore, the thin film substrate 100 is strongly coupled to thesupport substrate 500 in the adsorbing area SB, but is relatively moreweakly coupled with the release layer 10 in the desorbing area SA, suchthat after the thin film substrate 100 is cut into display panels 300,the display panels may be easily separated from the support substrate500.

FIG. 12 is a flowchart illustrating a sequence of manufacturing adisplay panel according to a third exemplary embodiment of the presentinvention and FIG. 13 is a cross-sectional view of the display panel inan intermediate step according to the sequence of FIG. 12. Hereinafter,only characteristic portions differentiated from the first exemplaryembodiment of FIG. 1 will be described in detail, and non-describedportions are the same as or similar to the first exemplary embodiment ofFIG. 1.

As illustrated in FIG. 12, the method for manufacturing a display panelaccording to the third exemplary embodiment includes forming a recessportion in the support substrate (S300), cleaning the substrate (S302),bonding the thin film substrate to the support substrate (S304), formingthe pixel including the thin film transistor on the thin film substrate(S306), cutting the thin film substrate into individual display panels(S308), and separating the display panels from the support substrate(S310).

That is, according to the third exemplary embodiment of FIG. 12, adetaching recess portion 20 is formed in the support substrate 500 asillustrated in FIG. 13. When the detaching recess portion 20 is formed,a region corresponding to the detaching recess portion becomes thedesorbing area SA, and other regions become the adsorbing area SB.

The detaching recess portion 20 may be formed by plasma etching for 300seconds using CF₄ gas or mixed gas of CF₄ and Ar, or may be formed bysandblast etching using particles having a size of 1 μm or less.

In this case, a depth of the detaching recess portion 20 may be formedin a range of 2 nm to 200 μm. When the depth of the detaching recessportion is 200 μm or more, the thin film substrate may crack due to thestep, and when the depth of the detaching recess portion is 2 nm orless, the detaching may not be facilitated.

As described above, when the recess portion 20 is formed and then thethin film substrate 100 is disposed, the thin film substrate 100 isstrongly coupled with the support substrate 500 only in the adsorbingarea SB external to the recess, whereas an empty space or a gap ispresent between the thin film substrate 100 and the support substrate500 in the desorbing area SA due to the recess portion 20, such that thethin film substrate 100 is not strongly coupled to the support substrate500 in desorbing area SA. Therefore, after the display panel 300 isformed, the support substrate 500 may be easily separated from thedisplay panel 300.

The third exemplary embodiment describes, by way of example, that therecess portion is formed and then the substrate is cleaned. However, thepresent invention is in no way so limited, and as with the secondembodiment of FIG. 10, a fourth embodiment can be created where thesubstrate 500 may be cleaned first and then the recess portion 20 maythen be formed, such that only the adsorbing area SB may have thehydrophilicity.

While this disclosure has been described in connection with what ispresently considered to be practical exemplary embodiments, it is to beunderstood that the invention is not limited to the disclosedembodiments, but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

DESCRIPTION OF SYMBOLS

-   -   10: Release layer    -   20: Recess portion    -   70: Organic light emitting element    -   85: contact hole    -   100: Substrate    -   110: buffer layer    -   120: Pixel    -   121: first signal line    -   135: semiconductor    -   140: gate insulating layer    -   155: gate electrode    -   160: first interlayer insulating layer    -   166: source contact hole    -   167: drain contact hole    -   171: data line    -   172: driving voltage line    -   176: source electrode    -   177: drain electrode    -   180: second interlayer insulating layer    -   190: pixel definition layer    -   195: opening    -   260: sealing member    -   300: Display panel    -   400: Driver    -   500: Support substrate    -   710: first electrode    -   720: organic emission layer    -   730: second electrode    -   1355: channel region    -   1356: source region    -   1357: drain region

What is claimed is:
 1. A method of manufacturing a display panel,comprising: defining a desorbing area in a support substrate by formingone of a release layer and a recess portion in the desorbing area of thesupport substrate; cleaning a surface of the support substrate;disposing a thin film substrate on the support substrate; bonding thethin film substrate to the support substrate; forming a pixel and asealing member on the thin film substrate; cutting the sealing memberand the thin film substrate at a location that corresponds to thedesorbing area; and separating the support substrate from the thin filmsubstrate.
 2. The method of claim 1, wherein the cleaning being achievedby a process selected from a group consisting of UV cleaning, ultrasonicwave cleaning, waterjet cleaning, hydrogen water cleaning, and ozone(O₃) cleaning.
 3. The method of claim 1, wherein the desorbing area isdefined by the recess portion, the recess portion being produced byetching the support substrate via a process selected from plasma etchingand sandblasting.
 4. The method of claim 3, wherein a depth of therecess portion is 2 nm to 200 μm.
 5. The method of claim 1, wherein thedesorbing area is defined by the release layer, the forming of therelease layer comprises: forming one of an indium tin oxide (ITO) layerand an indium zinc oxide (IZO) layer on the support substrate; forming areserved release layer by patterning the one of the ITO layer and theIZO layer; and crystallizing the reserved release layer.
 6. The methodof claim 5, wherein the release layer is formed to have a thickness of100 Å to 1,000 Å.
 7. The method of claim 1, wherein the thin filmsubstrate comprises an ultrathin glass having a thickness of 0.01 mm to0.1 mm.
 8. The method of claim 1, wherein a surface roughness of thesupport substrate at a location corresponding to an adsorbing areaexternal to the desorbing area is equal to or less than 0.2 nm.
 9. Themethod of claim 8, wherein the support substrate includes an adsorbingarea surrounding the desorbing area, wherein during the bonding, thethin film substrate is directly and covalently bonded to the supportsubstrate in the adsorbing area without an intervening adhesive layer.10. The method of claim 1, wherein the pixel includes an organic lightemitting element.
 11. A method of manufacturing a display panel,comprising: cleaning a surface of a support substrate; defining adesorbing area of the support substrate by forming one of a releaselayer and a recess portion in the desorbing area of the supportsubstrate; disposing a thin film substrate on the support substrate;bonding the thin film substrate to the support substrate; forming apixel and a sealing member on the thin film substrate; cutting thesealing member and the thin film substrate at a location thatcorresponds to the desorbing area; and separating the support substratefrom the thin film substrate.
 12. The method of claim 11, wherein thecleaning comprises a process selected from a group consisting of UVcleaning, ultrasonic wave cleaning, waterjet cleaning, hydrogen watercleaning, and ozone (O₃) cleaning, wherein the thin film substrate isdirectly and covalently bonded to the support substrate in an adsorbingarea external to the desorbing area and without an intervening adhesivelayer.
 13. The method of claim 11, wherein the desorbing area is definedby the recess portion, the recess portion being produced by etching thesupport substrate via a process selected from a group consisting ofplasma etching and sandblasting.
 14. The method of claim 13, wherein adepth of the recess portion is 2 nm to 200 μm.
 15. The method of claim11, wherein the desorbing area is defined by the release layer, theforming of the release layer comprises: forming one of an indium tinoxide (ITO) layer and an indium zinc oxide (IZO) layer on the supportsubstrate; forming a reserved release layer by patterning the one of theITO layer and the IZO layer; and crystallizing the reserved releaselayer.
 16. The method of claim 15, wherein the release layer is formedto have a thickness of 100 Å to 1000 Å.
 17. The method of claim 11,wherein the thin film substrate is an ultrathin glass having a thicknessof 0.01 mm to 0.1 mm.
 18. The method of claim 11, wherein a surfaceroughness of the support substrate at a location corresponding to anadsorbing area external to the desorbing area is equal to or less than0.2 nm.
 19. The method of claim 11, wherein the support substratefurther includes an adsorbing area surrounding the desorbing area. 20.The method of claim 11, wherein the pixel includes an organic lightemitting element.